I'm working on a series of maps of differing scales and different labels.  In my head I'm thinking, I'll just do one map, use bookmarks for each individual map, and annotation groups with zoom scales set.  That way I could just use the same background symbology, and just label at different scales where needed.  How come things are never easy as they are in my head?  I exported my first map to see how they were turning out.  Nothing, no labels, just the background layers.  After some mucking about it seemed to be a problem of setting the zoom scales.  I used the scale of 1:110,000 because that's what everything was set at.  Well, you can't do that, you need to have the Out Beyond and In Beyond buffer the scale of your map.  Why is this actually a huge problem?  It indicates that ArcMap doesn't export at the scale you set.  This makes you a liar, or at least your scale bar a liar.  This happens on occasion when you close ArcMap and reopen the same mxd.  Noticed those scale numbers bounced around a bit, and your scale bar changed?  I guess ArcMap does it for exports too.  This is actually a good reason to use a graphics scale bar rather than text based.  Your scale bar should shift slightly with the export...at least in theory.